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What is Reflection?


Light travels in a straight line through substances of the same medium. This movement is called rectilinear propogation. When light hits on a flat surface, or is incident to the surface, it behaves like other waves and reflects. There are two types of reflection; specular reflection and diffuse reflection. Physics 30 will deal only with specular reflection
Bottom left:The ray diagram labels the need to know terms of specular reflection.
Bottom right: An example of Diffuse Reflection
reflection.jpg diffuse.png
Incident Ray: This is the original wave of light that will hit the surface and reflect.
Reflected Ray: The resulting ray after the Incident Ray hits the reflective surface.
Point of Incidence (Not labeled due to space): The point at which the reflection occurs and at the Incident Ray becomes the Reflected Ray.
Normal: The invisible line that separates the Incident Ray from the Reflected Ray
Angle of Incidence: The angle that the Incident Ray is to the Normal
Angle of Reflection: The angle that the Reflected Ray is to the Normal

Law of Reflection

The law of reflection states that: The angle of reflection is equal to the angle of incidence and is in the same plane. The law of reflection helps explain how images are created from mirrors.

Image Formation on a Plane Mirror

When an image is reflected in a mirror, are you really seeing a real image? No, although it appears that light rays are originating from the image behind the mirror, your brain is being tricked into thinking that the image is real. The image behind the mirror is called a virtual image. The virtual image only exists behind the mirror and cannot be cast onto a diffusely reflecting surface. A real image on the other hand can be projected onto diffusely reflecting surfaces. An excellent example of an object that produces real images is a projector.
Bottom Left: An example of a virtual image
Bottom Right: An example of a real image
external image aqa_phy_ray-diagram.jpg
external image 2435560-981576-bar-graph-projected-on-a-businessman.jpg

Image Characteristics

The images that are formed from reflection take on certain characteristics that affect how the real or virtual image appears:
Magnification: the relation between the size of the image and the size of the object. Can be the same size, diminished or enlarged.
Attitude: Whether the image is erect (upright) or inverted (upside down) relative to the object.
Position: Where the image forms relative to the surface of the mirror.
Type: Whether the image is virtual or real.

For more information on Reflection, address Mr. Langdale's note package on reflection "P30 EMR Reflection and Refraction".
For more information on images generated from reflection visit Concave Mirrors and the not yet added Convex Mirrors pages.

wiki by George Heacock
References

  1. http://www.annemckinnell.com/blog/wp-content/uploads/2011/03/convictlk_20100920__MG_2064.jpg
  2. http://1.bp.blogspot.com/_EObJM5duFU8/SIcxcclu8iI/AAAAAAAACds/OMWU-o3cip8/s400/reflection.jpg
  3. http://twistedphysics.typepad.com/.a/6a00d8341c9c1053ef0115707a8bf0970b-pi
  4. http://www.bbc.co.uk/schools/gcsebitesize/science/images/aqa_phy_ray-diagram.jpg
  5. http://www.colourbox.com/preview/2435560-981576-bar-graph-projected-on-a-businessman.jpg